Global Patent Index - EP 0973128 A2

EP 0973128 A2 20000119 - Histogram-based intensity expansion

Title (en)

Histogram-based intensity expansion

Title (de)

Auf Histogrammen beruhende Helligkeitserweiterung

Title (fr)

Extension d'intensité basé sur histogrammes

Publication

EP 0973128 A2 (EN)

Application

EP 99201949 A

Priority

US 9015198 P

Abstract (en)

A method and apparatus for selectively scaling portions of image data based on the intensity levels of historical image data. The selective scaling, or level expansion, provides improved images by increasing or decreasing the intensity of a portion of image pixels. Black level expansion reduces the intensity of dark pixels and is appropriate when a relatively large number of the image pixels have a high intensity level. White level expansion increases the intensity of bright pixels and is appropriate when a relatively large number of image pixels have a low intensity level. Level expansion is implemented by using histogram comparators 402 to compare the intensity of each pixel with a threshold, typically on a frame-by-frame basis. When an adequate number of pixels in each frame meet the threshold criteria, the level expansion is increased. Field accumulator 404 is used to determine whether and by how much the image data is scaled. Field accumulator 404 increments each time a frame meets the expansion criteria, as determined by the histogram comparators 402, and decrements each time a frame does not meet the expansion criteria. The value accumulated by the field accumulator 404 is used by level expander 406 to scale at least a portion of the input data. <IMAGE>

IPC 1-7

G06T 5/40

IPC 8 full level

G09G 5/36 (2006.01); G06T 5/00 (2006.01); G06T 5/40 (2006.01)

CPC (source: EP)

G06T 5/009 (2013.01); G06T 5/40 (2013.01); G06T 2207/10016 (2013.01)

Designated contracting state (EPC)

DE FR GB IT NL

DOCDB simple family (publication)

EP 0973128 A2 20000119; EP 0973128 A3 20001018; EP 0973128 B1 20030611; DE 69908713 D1 20030717; DE 69908713 T2 20040513; JP 2000029449 A 20000128; US 2002101432 A1 20020801; US 6529211 B2 20030304

DOCDB simple family (application)

EP 99201949 A 19990617; DE 69908713 T 19990617; JP 17468599 A 19990621; US 33816599 A 19990622